Improvement i



LR. HoFFMAN-` BANDSAW MILL.

192.917. Patented-Ju1y10, 18 7.

VLPETERS. PHoTo-LITHOCRAPHER, WASMINGYON, D. C.

UNITED N Sr JAGQB a HOFFMAN, 0F 4Foln WAYNEJNDIANA.

IMPROVEMENT BANDfSAW MILLS.

Specification forming part of Letters Patent No. 92,9i7, dated J uly`10, 1877; application Afiled May 21, 1877.

17o all whom it. maycoucein;

Bc. itlniownthat I, .JAcon R. HOFFMAN, of Fort Wa-yne, county of Allen,and ttateof lndiana, have invented a new and useful I mprovementinBand-SawpMiill, of which the fol# lowing is a specification: v

Inthe accompanying drawings,F igure 1 represents a side elevation lof my.improved band-saw mill, partlyinsection, online a' m, Fig. 2. Fig. 2 isan end view in section on line y y, Fig. l, and Figs. 3 and 4 are detailhorizontal sections on lilies y y, Fig. 2, and la k, Fig. 1,illustrating the horizontal adjustment of upper band-saw pulley.

Similar letters of reference indicate correspondin g parts.

The object of this invention is to improve the construction of band-sawmills, that the strain of the saw is accomplished, in place of applyinga greater weight, by employing the upper sawpulley for the purpose ofdriving -the feed or any other mechanism, giving there by the saw ahigher tension or strain, and rendering the same less liable to idodge77in going through the log. The friction on the bearings of the upperpulley-shaft is thereby reduced, and either the front or back edge ofthe saw strained' at will for forward or backward motion. The feedmotionis also improved especially with a view to facilitate the gigging7 backof the log-carriage.

The invention consists, essentially, in the combination ot' the uppersaw-pulley, by suitable transmissions, with the feed mechanism of thesaw-carriage or other movements, using power so as to strain the saw atthe same time. It next consists of the horizontal adjustment ofthe upperpulley-shai't-supporting frame, so as to strain the front or back edgeofthe saw 5 Y and, dually, ofthe combinationof the feeding mechanismwith an inclined way, to facilitate the gigging back.

In the drawings, A represents the supporting main post, and A thegirders, level with door. The band-saw B is stretched over a lowerdriving pulley, C, and an upper straining-pulley, C', and the strainequalized by a weight-and-lever attachment of the upper shaft-supportingframe D, that provides for the contraction and expansion of the saw. TheframeD, which supports the shaft of the I upper pulley, is hungtoverticalrodsDlof l horizontal blckets D2. AThe bearings aoftheupperpulley-,shaft .are `mail@ adjustable in frame D by means`ofscrew-rod l, soasto im- ,part 1to .the shaftan `oscillatingmotioinand throw thereby the saw-pulley out of perpendicnlar position,`which adjustment enables the operator to vequalize the strainion allparts .y

of its width. This feature has been fully described in a patentheretofore granted to me under date of December 20, 1870, and No.110,236.

The upper sawpulley C transmits, by a grooved wheel, E, keyed to theshaft orI made in one piece with pulley C', and belt-motion to a secondwheel, El, whose shaft is supported on arms lil2 of frame D, whichlatter is adjusted on the supporting-rods as the length of the sawrequires. Theshaft of the wheel El is provided at therouter end with asecond grooved wheel, E3, that transmits by a belt, in connection withvertically-adjustable guidepulleys e, motion to the grooved wheelF ofVthe feed-shaft F, which moves, by a friction cord and pulley, thelog-carriage G forward and back on the inclined way G'.

The guide-pulleys e are arranged at a suitable angle of inclination toeach other, and the supporting-bearings of the same moved up or down onguide-rods f, to suit length of saw. The upper saw-pulley drives thus,by the intermediate transmitting parts, the log-carriage, and givesthereby the saw a higher tension or strain without the employment ofadditional weights for that purpose, while it also reduces the frictionon the bearings instead of increasing it, as would be the case by theaddition of weights to the straining-lever.

The transmittingbelt of the Wheel next to the saw-pulley pulls inopposite direction to the motion of the saw, and tends thereby tosuspend or balance the shaft in its bearings,

so as to diminish the friction.

As the log-carriage works on an inclined way, all the power required formoving the log back and forth is expended in feeding up,

throwing thereby the strain on the saw when the same is moving' throughthe log, where it is required. The carriage is readily gigged back inthe inclined track, While ordinarily it takes greater power to gig backthan to feedl up.

rrron. N

' eccentricity of which is extended below the brackets and pro-v videdwith a small pinion geared by a wormwheel or otherwise, so as to allowthe ready swinging of the supporting-frame D by the the outer rod Dl onthe inner pivoted rod D1. The rod D1 passes through a slot of frame D,as shown in Fig. 3, the adjusting-gear being shown 1n Fig. 4.

The turning of the gear imparts to the supporting-frame D a throw inhorizontal direction, which is an important feature, as it adjusts theupper saw-pulley so that the saw can work forward or back on the wheelat the pleasure of the sawyer, without straining either edge, whichlatter result is only accomplished by the employment of the device forgiving the upper pulley the vertical movement.

Having thus fully described my invention, I

v claim as new and desire to secure by Letters Patent- 1., In a band-sawmill, the combination of the upper saw-pulleyT C with the log or feedcarriage G, and mechanism, substantially as described, for operatingsaid carriage from the saw-pulley, for the purpose of straining the saw,as and for the purpose set forth.

2. The combination, in a band-saw mill, of the inclined way Gr',log-carriage Gr, band-saw B, lower pulley C, upper straining saw-pulleyand suitable transmitting mechanism for operating the, log-carriagefroml the upper strain-pulley, substantially as and for the purpose setforth.

3. The combination of the outer eccentrically-pivoted rod, D1, and innerpivot-rod D1, and suitable operating-gear, with the shaftsupportingframe D, upper saw-pulley C', for

imparting horizontal motion to the latter, for the purpose described.

J AGOB R. HOFFMAN.

Witnesses:

WM. H. HOFFMAN, J oHN B.. HOAGLAND.

